The present invention relates to a temperature sensor applicable in a variety of applications such as fire alarm equipment and air conditioning equipment.
Various types of temperature sensors have been used in home fire alarm systems and home air conditioning systems, respectively. In order to eliminate time-consuming installation and to decrease installation expense, there arises a demand for a single temperature sensor used for both the fire alarm system and the air conditioning system. However, a temperature sensor for a fire alarm system must be used in a wide temperature range (e.g., 40.degree. C. to 90.degree. C.), but is not required to generate highly precise detection signals, as compared with detection signals generated by a temperature sensor for an air conditioning system. Although the temperature sensor for the air conditioning system must produce a highly precise signal (resolution of the signal must be given in units of 0.1.degree. C.), it can be used in a narrow temperature range (e.g., 10.degree. C. to 30.degree. C.). In this manner, the temperature sensors for the alarm system and the air conditioning system have different specifications. As a result, many problems are presented when a single temperature sensor is used for both the first alarm system and the air conditioning system. In order to eliminate these problems, a single temperature sensor which can be used in the temperature range of 10.degree. C. to 90.degree. C. and can detect signals in units of 0.1.degree. C. is required. However, the manufacturing cost of such a temperature sensor is high, and the amount of transmission data is greatly increased.